Jeep 1997 Grand Cherokee Service Manual page 384

8E - 18 INSTRUMENT PANEL SYSTEMS
DIAGNOSIS AND TESTING (Continued)
COOLANT LEVEL LOW/COOLANT SENSOR
BAD
If the problem being diagnosed is related to lamp
accuracy, be certain to confirm that the problem is
with the lamp and sensor and not with the engine
coolant level. The actual engine coolant level should
be checked before you proceed with lamp and sensor
diagnosis. Refer to 8W-46 - Message Center in Group
8W - Wiring Diagrams for complete circuit descrip-
tions and diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO
RESTRAINT SYSTEMS
STEERING WHEEL,
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Unplug the coolant level sensor wire harness
connector on the coolant reserve bottle. Check for
continuity between the ground circuit cavity of the
wire harness connector and a good ground. There
should be continuity. If OK, go to Step 2. If not OK,
repair the open circuit as required.
(2) With the engine coolant at the proper level,
check the resistance between the two terminals of
the coolant level sensor. The resistance should be
3000 to 3500 ohms. If OK, go to Step 3. If not OK,
replace the faulty sensor.
(3) Disconnect and isolate the battery negative
cable. Remove the VIC module as described in this
group. Unplug the VIC module wire harness connec-
tor. Check for continuity between the engine coolant
level switch sense circuit cavity of the VIC wire har-
ness connector and a good ground. There should be
no continuity. If OK, go to Step 4. If not OK, repair
the short circuit as required.
(4) Check for continuity between the engine cool-
ant level switch sense circuit cavities of the VIC wire
harness connector and the engine coolant level sensor
wire harness connector. If OK, replace the faulty VIC
module. If not OK, repair the open circuit as
required.
FOUR-WHEEL DRIVE DISPLAY AND
INDICATORS/SERVICE 4WD SWITCH
If the problem being diagnosed is related to an
incorrect or no four-wheel drive display or indicator
functions, be certain to confirm that the problem is
with the VIC module and transfer case switch cir-
cuits, and not with a Powertrain Control Module
(PCM) with an incorrect Vehicle Identification Num-
ber (VIN). This condition can only occur if the origi-
nal PCM was replaced with a unit from another
GROUP 8M - PASSIVE
BEFORE ATTEMPTING
STEERING COLUMN,
vehicle. The VIC module uses the VIN message
received on the CCD data bus from the PCM to
determine if the vehicle is equipped with two-wheel
drive or four-wheel drive.
If a four-wheel drive vehicle has a two-wheel drive
VIN entered in the PCM, the VIC will ignore all
transfer case switch inputs. If a two-wheel drive
vehicle has a four-wheel drive VIN entered in the
PCM, the rear wheels in the VIC display will not
light. Use a DRB scan tool and the proper Power-
train Diagnostic Procedures manual to confirm the
VIN in the PCM.
In addition, it should be noted that a VIC "Service
4WD Switch" message on a two-wheel drive vehicle
OR
can occur if a short circuit occurs in the transfer case
switch circuits from the VIC module, in combination
with a PCM having a four-wheel drive VIN. To locate
the short circuit, start at Step 3 of the following diag-
nostic procedure. Two-wheel drive models do have
the same VIC wire harness provisions as four-wheel
drive models.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER
RESTRAINT SYSTEMS
STEERING WHEEL,
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Unplug the wire harness connector at the
transfer case switch. Check for continuity between
the ground circuit cavity of the transfer case switch
wire harness connector and a good ground. There
should be continuity. If OK, go to Step 2. If not OK,
repair the open circuit as required.
(2) Check the transfer case switch continuity while
shifting the transfer case shift lever to the proper
positions. The switch continuity should be as shown
in (Fig. 2). If OK, go to Step 3. If not OK, replace the
faulty switch.
(3) Disconnect and isolate the battery negative
cable. Remove the VIC module as described in this
group. Unplug the VIC module wire harness connec-
tor.
(4) Locate two pairs of wire harness connectors
located in the wire harness leading to the VIC mod-
ule. The wire harness connectors should be taped
back to the harness. One pair of connectors are black
with a single cavity. The other pair are red with two
cavities. If the vehicle has the Quadra-Trac 4WD
transfer case, only the red wire harness connectors
should be joined. If the vehicle has the Command-
Trac or Selec-Trac 4WD transfer case, only the black
wire harness connectors should be joined. In all
TO GROUP 8M -
BEFORE ATTEMPTING
STEERING COLUMN,
ZG
PASSIVE
OR